We suggest starting out by practicing on a lock with a known combination which "follows the rules" and opens using this method. The best way to practice is not to know the combination yourself, but have a friend know the combination and check your work as you go along.

There are a few locks that won't open using these methods. Master Lock Company redesigned the locks, and the redesigned locks began appearing on store shelves in 1999 or 2000. These methods most likley* do not work on the redesigned locks. However, we bought some locks in August, 2003, and all of the locks opened using the "old" methods. The locks that we purchased appeared to be recently manufactured. It appears that Master went back to the earlier design, even for its new "sphero" and "Titanium Series" locks. In fact, the "sphero" and "Titanium Series" locks, despite their higher selling prices, appear to be easier to open, using these methods, than the original "1500 series" locks.

The redesigned "1500 series" locks that don't open using these methods can be distinguished from the others by serial numbers beginning with 800, on the backs of the locks. See below.

The locks with serial numbers beginning with 800, and locks from other manufacturers, can be opened, and we provide a method, on this site, for finding the combinations. However, we suggest trying this method first on all Master Locks. If you are practicing the method for the first time, to avoid the frustratration of not being able to open the lock, be sure to select a lock that will work with these methods.

If you purchase a lock, have a friend remove the combination sticker from the back of the lock, then check the serial number. Acccording to "Carl," the following Master Lock serial numbers will work for these methods:

Five digit serial numbers, including those preceeded by X.
Six digits starting with 90 or 91.
Seven digits starting with 120.
Locks with no serial number or with a keyhole on the back.

As of August, 2003, we are adding:
"sphero" and "Titanium Series" locks with any serial number will open, based on the locks we have tried.

The following most likely* will not work:

Serial numbers with 7 digits beginning with 800. (Even if the lock has a keyhole on the back, we suspect that these serial numbers will not work.)

Model 2002 and 2010 "high security" combination padlocks. Click here for special instructions on how to find the combinations for these locks.

The "1500" series locks that we purchased in August, 2003, had 6 digits starting with 90.

Locks with Keyholes


Locks with keyholes can be opened either by dialing the correct combination or by inserting and turning the correct key. These locks are often used in schools. The school administrator's key will open any lock in the system. The keyhole is an extra part that has been added to a lock. Otherwise, the lock almost the same as the lock without a keyhole.

Locks with a keyhole have two serial numbers, one above the other. The lower serial number, which starts with V on my locks, is, apparently, for the key. In other words, locks with the same lower serial number will open with the same key.

So far, all locks with keyholes that have come to our attention will open using this method. However, most of the keyhole locks in use were probably manufactured before Master Lock redesigned the lock. So, we don't know if Master introduced the new design into its locks with keyholes.

Glossary of terms:

Shackle: The U shaped piece, at the top in the picture.
Body: The rest of the lock (excluding the shackle)
Right: Clockwise
Left: Counterclockwise

Review on opening the lock when the combination is known:

Turn the dial right at least two turns and stop at the first number in the combination.
Turn the dial left one turn and continue turning to stop at the second number in the combination.
Turn the dial right to and stop at the third number in the combination.
Pull up on the shackle (or down on the body) of the lock.

Now the good part: How to find the combination!


Finding the combination is a two step process:

1) Determine the last number in the combination

2) Try up to 64 possible combinations that have that last number. (About half the time, the combination will be found in 32 tries or less.)

Click here to proceed to the next step: Finding the last number of the combination.

*From combinations provided to us, it appears that there are a few redesigned locks that can be opened by the methods for the "old" locks, but these locks are greatly outnumbered by locks that can't.
Identifying Locks Will Open Using This Method, and Which Most Likely* Won't